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<div class="title">IPv4<div class="ingroups"><a class="el" href="group__lwip.html">lwIP</a> &raquo; <a class="el" href="group__lwip__opts.html">Options (lwipopts.h)</a></div></div>  </div>
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Macros</h2></td></tr>
<tr class="memitem:ga429e811a80ebb5157e14a854870c4410"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#ga429e811a80ebb5157e14a854870c4410">LWIP_IPV4</a>&#160;&#160;&#160;1</td></tr>
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<tr class="memitem:ga881d32ff5ee02af01f758953f1b51d59"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#ga881d32ff5ee02af01f758953f1b51d59">IP_FORWARD</a>&#160;&#160;&#160;0</td></tr>
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<tr class="memitem:gaa956b0167c37a2265b55e2d0204a3933"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#gaa956b0167c37a2265b55e2d0204a3933">IP_OPTIONS_ALLOWED</a>&#160;&#160;&#160;1</td></tr>
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<tr class="memitem:gad41122bd0b5485a18a4415c8f953727b"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#gad41122bd0b5485a18a4415c8f953727b">IP_REASS_MAXAGE</a>&#160;&#160;&#160;15</td></tr>
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<tr class="memitem:ga556b9b58fd02c0fdd126791baef77411"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#ga556b9b58fd02c0fdd126791baef77411">IP_DEFAULT_TTL</a>&#160;&#160;&#160;255</td></tr>
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<tr class="memitem:ga0b2c993fd940f5774108298933310384"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#ga0b2c993fd940f5774108298933310384">IP_SOF_BROADCAST</a>&#160;&#160;&#160;0</td></tr>
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<tr class="memitem:ga9e761df07c4e93901858741d4771dbc7"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__lwip__opts__ipv4.html#ga9e761df07c4e93901858741d4771dbc7">IP_FORWARD_ALLOW_TX_ON_RX_NETIF</a>&#160;&#160;&#160;0</td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<h2 class="groupheader">Macro Definition Documentation</h2>
<a id="ga556b9b58fd02c0fdd126791baef77411"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga556b9b58fd02c0fdd126791baef77411">&#9670;&nbsp;</a></span>IP_DEFAULT_TTL</h2>

<div class="memitem">
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          <td class="memname">#define IP_DEFAULT_TTL&#160;&#160;&#160;255</td>
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<p>IP_DEFAULT_TTL: Default value for Time-To-Live used by transport layers. </p>

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<h2 class="memtitle"><span class="permalink"><a href="#ga881d32ff5ee02af01f758953f1b51d59">&#9670;&nbsp;</a></span>IP_FORWARD</h2>

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          <td class="memname">#define IP_FORWARD&#160;&#160;&#160;0</td>
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<p>IP_FORWARD==1: Enables the ability to forward IP packets across network interfaces. If you are going to run lwIP on a device with only one network interface, define this to 0. </p>

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<h2 class="memtitle"><span class="permalink"><a href="#ga9e761df07c4e93901858741d4771dbc7">&#9670;&nbsp;</a></span>IP_FORWARD_ALLOW_TX_ON_RX_NETIF</h2>

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<div class="memproto">
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          <td class="memname">#define IP_FORWARD_ALLOW_TX_ON_RX_NETIF&#160;&#160;&#160;0</td>
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<p>IP_FORWARD_ALLOW_TX_ON_RX_NETIF==1: allow ip_forward() to send packets back out on the netif where it was received. This should only be used for wireless networks. ATTENTION: When this is 1, make sure your netif driver correctly marks incoming link-layer-broadcast/multicast packets as such using the corresponding pbuf flags! </p>

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<a id="gaf85c8bdd5035b6cada790b4cc2a209a4"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gaf85c8bdd5035b6cada790b4cc2a209a4">&#9670;&nbsp;</a></span>IP_FRAG</h2>

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          <td class="memname">#define IP_FRAG&#160;&#160;&#160;1</td>
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<p>IP_FRAG==1: Fragment outgoing IP packets if their size exceeds MTU. Note that this option does not affect incoming packet sizes, which can be controlled via IP_REASSEMBLY. </p>

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<a id="gaa956b0167c37a2265b55e2d0204a3933"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gaa956b0167c37a2265b55e2d0204a3933">&#9670;&nbsp;</a></span>IP_OPTIONS_ALLOWED</h2>

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          <td class="memname">#define IP_OPTIONS_ALLOWED&#160;&#160;&#160;1</td>
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<p>IP_OPTIONS_ALLOWED: Defines the behavior for IP options. IP_OPTIONS_ALLOWED==0: All packets with IP options are dropped. IP_OPTIONS_ALLOWED==1: IP options are allowed (but not parsed). </p>

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<a id="ga29084a46d7d4be30e8029d356bca0394"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga29084a46d7d4be30e8029d356bca0394">&#9670;&nbsp;</a></span>IP_REASS_MAX_PBUFS</h2>

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          <td class="memname">#define IP_REASS_MAX_PBUFS&#160;&#160;&#160;10</td>
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<p>IP_REASS_MAX_PBUFS: Total maximum amount of pbufs waiting to be reassembled. Since the received pbufs are enqueued, be sure to configure PBUF_POOL_SIZE &gt; IP_REASS_MAX_PBUFS so that the stack is still able to receive packets even if the maximum amount of fragments is enqueued for reassembly! When IPv4 <em>and</em> IPv6 are enabled, this even changes to (PBUF_POOL_SIZE &gt; 2 * IP_REASS_MAX_PBUFS)! </p>

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<a id="gad41122bd0b5485a18a4415c8f953727b"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gad41122bd0b5485a18a4415c8f953727b">&#9670;&nbsp;</a></span>IP_REASS_MAXAGE</h2>

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          <td class="memname">#define IP_REASS_MAXAGE&#160;&#160;&#160;15</td>
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<p>IP_REASS_MAXAGE: Maximum time (in multiples of IP_TMR_INTERVAL - so seconds, normally) a fragmented IP packet waits for all fragments to arrive. If not all fragments arrived in this time, the whole packet is discarded. </p>

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<h2 class="memtitle"><span class="permalink"><a href="#ga1a31ab0e0f37b17d40fa7c35bc2c4f69">&#9670;&nbsp;</a></span>IP_REASSEMBLY</h2>

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          <td class="memname">#define IP_REASSEMBLY&#160;&#160;&#160;1</td>
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<p>IP_REASSEMBLY==1: Reassemble incoming fragmented IP packets. Note that this option does not affect outgoing packet sizes, which can be controlled via IP_FRAG. </p>

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<h2 class="memtitle"><span class="permalink"><a href="#ga0b2c993fd940f5774108298933310384">&#9670;&nbsp;</a></span>IP_SOF_BROADCAST</h2>

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          <td class="memname">#define IP_SOF_BROADCAST&#160;&#160;&#160;0</td>
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<p>IP_SOF_BROADCAST=1: Use the SOF_BROADCAST field to enable broadcast filter per pcb on udp and raw send operations. To enable broadcast filter on recv operations, you also have to set IP_SOF_BROADCAST_RECV=1. </p>

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<a id="ga0f1fbf42d3344bf87cd056d48ddca3db"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga0f1fbf42d3344bf87cd056d48ddca3db">&#9670;&nbsp;</a></span>IP_SOF_BROADCAST_RECV</h2>

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          <td class="memname">#define IP_SOF_BROADCAST_RECV&#160;&#160;&#160;0</td>
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<p>IP_SOF_BROADCAST_RECV (requires IP_SOF_BROADCAST=1) enable the broadcast filter on recv operations. </p>

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<h2 class="memtitle"><span class="permalink"><a href="#ga429e811a80ebb5157e14a854870c4410">&#9670;&nbsp;</a></span>LWIP_IPV4</h2>

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          <td class="memname">#define LWIP_IPV4&#160;&#160;&#160;1</td>
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<p>LWIP_IPV4==1: Enable IPv4 </p>

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